Communication networks are currently evolving from circuit switched (CS) networks towards packet switched (PS) networks, in particular Internet Protocol (IP) based networks. For example, the LTE (Long Term Evolution) radio access technology as specified by 3GPP (3rd Generation Partnership Project) no longer supports CS connections to a user equipment (UE) but only IP based PS connections. To offer voice support, also technologies allowing voice communication over PS connections have been introduced. Examples of such technologies are VoIP (Voice over IP) and more specifically VoLTE (Voice over LTE).
In addition to voice communication, also enhanced multimedia services may be supported for packet based calls. For example, a mobile network may be augmented with an IMS (IP Multimedia Subsystem) as specified in 3GPP Technical Specification (TS) 23.228 V12.0.0. The IMS allows for establishing a voice call that is augmented with multimedia features. For example, the voice communication of the call may be supplemented by exchange of multimedia content, such as pictures, video clips, text messages, or the like, between the call parties. For exchanging such multimedia content during the call, additional media sessions may be formed in a user plane of the call. Such additional user plane media sessions may be used for conveying media streams with the multimedia content. The control plane of the call and the user plane with all media sessions are managed by the IMS. If the end devices of the call are mobile phones or some other type of UE for the mobile network, the control plane and the user plane of the call are carried over infrastructure of the mobile network, e.g., the radio access network and core network.
However, in some cases such multimedia enhancements as provided by the IMS may not be utilized to the full extent. For example, the UE may not be able to use multimedia content in the form of a real-time video due to limited capacity of the radio access network or due to limited capacity of the core network. Further, limited display size or processing power of the UE may prevent adequate rendering of the multimedia content on the UE.
In order to address capacity limitations of the mobile network, solutions have been developed in which the data traffic of the call is offloaded to an alternative access network supported by the UE, e.g., to a Wireless Local Area Network (WLAN). In such cases, both the control plane and all media planes of the call would be established over the alternative access network. Further, the operator of the mobile network would still manage the offloaded traffic, e.g., by initiating charging or Quality of Service (QoS) control, or the like. However, this typically requires integrated infrastructure of the mobile network and the alternative access network, which is not always available.
Still further, for example “Real-Time Multimedia Session Splitting and Seamless Mobility in Session Initiation Protocol Environments” by T. Stähle et al., MMEDIA 2011: The Third International Conference on Advance in Multimedia”, IARIA, 2011, describes techniques which allow for splitting media streams of a VoIP call between multiple Session Initiation Protocol devices. However, such techniques require SIP support in all involved devices. Further, in these techniques usage of network based control instances such as the IMS is not considered at all.
Accordingly, there is a need for techniques which allow for improved utilization of multimedia enhancements of a packet based call.